One from Glasgow, perhaps, seen in racecourse (5)
I believe the answer is:
ascot
'racecourse' is the definition.
(British racecourse)
'one from glasgow perhaps' is the wordplay.
'one' becomes 'a' (a thing is one thing).
'from' means one lot of letters go next to another.
'glasgow perhaps' becomes 'scot' (I can't justify this - if you can you should give a lot more credence to this answer).
'a'+'scot'='ASCOT'
'seen in' is the link.
Can you help me to learn more?
(Other definitions for ascot that I've seen before include "Royal Berkshire race-meeting (and fashion show!)" , "Society race meeting" , "Tosca (anag) - racecourse" , "Where the Queen often sees racehorses" , "sporting venue" .)